Objects, equipment, machines, and/or gearboxes often require that a proper fluid level or lubrication level be maintained and conditioned for safe and effective operation. Maintaining the proper fluid level can reduce friction, over-heating, contamination, and wear of the internal mechanical components, and failure to maintain the proper fluid level can result in failure of the object and/or costly repairs. Often, objects themselves are opaque or are fully enclosed with opaque housings or enclosures that make visually inspecting the fluid level in the object difficult. Accordingly, fluid level sight gauges are commonly used to display the fluid level in the object.
The following U.S. Patents disclosed example fluid level visualization systems and example sight gauges.
U.S. Pat. No. 5,442,959 discloses a sight gauge placed between two spaced apart compression type fittings connected to a vessel to show the liquid level in the vessel. The sight gauge has an elongated tubular transparent tube shield and a slightly longer elongated transparent sight tube that is received within the sight tube shield. An upper and a lower connection plate are each telescopically received by the sight tube, the sight tube shield being captured between the connection plates. An upper and a lower nozzle member each have an opening to respectively capture the upper and lower ends of the sight tube. An upper and lower elastomeric O-ring is received on the sight tube positioned between the connection plates and the nozzle members. Bolts secure the nozzle member to the compression plates to squeeze the O-rings against the sight tube so that the sight tube retains and supports the tube shield. Each nozzle member has an elongated tubular portion that can be received in a compression fitting.
U.S. Pat. No. 6,758,092 discloses a fluid level verification apparatus for use on liquid filled containers and configured to reduce inherent mechanical stresses on the inspection tube and resist leakage due to environmental, chemical, thermal or mechanical expansion cycles by using a protective shield member to encase the inspection sight member, and also a method for permanently sealing the fluid level detection apparatus.
U.S. Pat. No. 6,928,716 discloses a fluid level verification apparatus for use on liquid filled containers and configured to reduce inherent mechanical stresses on the inspection tube and resist leakage due to environmental, chemical, thermal or mechanical expansion cycles by using a protective shield member to encase the inspection sight member, and also a method for permanently sealing the fluid level detection apparatus.